Second generation (2G) networks include Code Division Multiple Access (CDMA) and Global System for Mobile Communications (GSM) networks and provide a wireless connection for digital voice encoding. Third Generation (3G) mobile networks offer cellular data rates that approach a wired broadband connection. These 3G mobile networks are robust delivery mechanisms for a rich variety of services that are being offered around the world. From CDMA 2000-based networks to those based on WCDMA (Wide-band Code-Division Multiple Access), cellular users are able to access services and information that were once only available from a wired desktop computer. Using third generation technologies it is now possible to deliver applications and multimedia services, such as streaming video files and interactive television programming, to these mobile devices.
WCDMA is also referred to as Universal Mobile Telecommunications System (UMTS) and along with CDMA 2000 represent an evolution in terms of services and data speeds from today's 2G mobile networks. UMTS and CDMA 2000 third generation mobile technologies identified by the ITU (International Telecommunication Union) are expected to include capabilities and features such as: enhanced multimedia (voice, data, video, and remote control), usability on all popular modes (cellular telephone, e-mail, paging, fax, videoconferencing, and Web browsing), broad bandwidth and high speed (upwards of 2 Mbps) routing flexibility (repeater, satellite, LAN), operation at approximately 2 GHz frequencies, and roaming capability throughout Europe, Japan, and North America.
Today's mobile customers have already demonstrated a desire for “non-voice” and other new services. More than 24 billion text messages are sent every month, and now customers are choosing Multimedia Messaging Service (MMS), an evolution of text messaging that adds pictures and sound elements. CDMA 2000 and UMTS build on these first steps towards a mobile multimedia future, allowing operators to offer new services to consumers. The availability of these robust mobile networks and sophisticated handheld devices, coupled with increasing consumer demand for media content, has generated a need for improved methods of subscribing to multimedia programming and packaged content at a mobile device.
Limitations on Over-the-Air (OTA) resources and of available power and storage for mobile devices make unicast of content challenging for mobile devices.